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12 I 777X Static Test Building <br /> To reduce the risk of slope instability,we make the following recommendations regarding temporary <br /> excavation slopes: <br /> ■ Protect the slope from erosion with plastic sheeting for the duration of the excavation to minimize <br /> surface erosion and raveling; <br /> ■ Limit the maximum duration of the open excavation to the shortest time period possible;and <br /> ■ Place no surcharge loads (equipment, materials,etc.)within 10 feet of the top of the slope. <br /> Temporary Construction Dewatering <br /> Water collected and discharged during construction will include precipitation and may include perched <br /> water. We do not anticipate static groundwater to be within the planned excavation depths; however, <br /> it is not far below the excavation depths. We anticipate that water can be managed during <br /> construction using trenches,sumps, and pumps above the groundwater table. <br /> Foundation Construction <br /> Because of the variability of the site conditions observed in the soil explorations,we recommend that <br /> Hart Crowser be retained to observe exposed subgrades before footing construction to confirm that <br /> subsurface conditions and preparation are suitable for footing support using the design <br /> bearing pressures. <br /> The exposed subgrade should be carefully prepared and protected before concrete placement. Any <br /> visible organic material, debris, and other unsuitable material should be removed from the exposed <br /> subgrade. Loosening of the materials during construction could result in more settlement than <br /> estimated. It is important that foundation excavations be cleaned of loose or disturbed soil and water <br /> before placing concrete. <br /> During wet weather, it may be necessary to place a 2-to 4-inch-thick lean concrete mat in footing <br /> excavations to protect subgrade soils from being softened by water or construction activities after <br /> they are exposed and approved by Hart Crowser. Lean concrete should only be placed after the <br /> subgrade has been observed and accepted by Hart Crowser. <br /> Micropile Installation <br /> It is important to select an experienced micropile contractor. Proper installation of piles requires <br /> appropriate care and experience on the part of the contractor. We recommend that all foundation <br /> contractors bidding on the project demonstrate proficiency and experience. <br /> The completed pile is below the ground surface and cannot be observed during construction; <br /> therefore,judgment and experience must be used to determine its acceptability. We recommend <br /> close monitoring of installation procedures, such as installation sequence,casing withdrawal rate, <br /> grouting pressure, and quantity of grout used per pile. Variations from the established pattern, such <br /> as low grout pressure or excessive settlement of grout in a completed pile,would make the pile <br /> susceptible to rejection. <br /> 19106-01 <br /> May 29,2015 1ATOZOWW-A <br />